1. Technical Field
The present invention relates to an image forming apparatus having a tab sheet insertion function.
2. Description of the Related Art
There exist printing apparatuses that are capable of creating printed products by inserting between pages a tab sheet having a flat rectangular main body and a tab protruding at a specified position on a side of said main body. See Japanese Unexamined Patent Publication No. 2005-271259.
In such a printing apparatus, multiple sets of tab sheets consisting of, for example, five tab sheets, whose tab positions are sequentially offset from each other, are used as constituents and are placed in a sheet supply tray. If only first three tab sheets are used in a printing job, the remaining two tab sheets, i.e., the fourth and fifth tab sheets, become no longer necessary and must be discharged. This is because it is necessary to supply tab sheets starting with the first tab sheet of a set in the execution of the next print job.
In the printing apparatus disclosed in the document, tab sheets that became no longer necessary are discharged after all the pages of a printing job are printed and discharged.
The printing apparatus described in said document only discloses the technology for using the same type of tab sheets held in a single sheet supply tray. For example, there are cases where it is desired to insert different types of tab sheets at page positions denoting “chapter” breaks and page positions denoting “paragraph” breaks, so that it is necessary to supply the first tab sheet of a set at the first “paragraph” break of a chapter after tab sheets have been used for “paragraph” breaks of a “chapter.” Therefore, the method of discharging tab sheets that became no longer necessary after all the pages of a printing job have been printed and discharged is not applicable to a case where a plurality of types of tab sheets are used. In other words, the printing apparatus described in said document does not address to the technology of properly discharging the tab sheets that became no longer necessary in a case where a plurality of types of tab sheets is used.